C'mon guys, this is a legitimate question. If I can paraphrase; "What are the advantages and disadvantages of putting multiple schemas on one database instead of on seperate databases?"


Originally posted by TomazZ
You have 8 instances meaning 8 databases on one box?
For performance sake it would definitely be better to have one database with 8 tablespaces.
Why? Each database would have it's own memory dedicated to it. You could tune each instance for maximum performance.

Originally posted by richyip
This is really not recommended. Why your customer needs to have 8 databases?
Again, Why?

Originally posted by raf
I think that avoiding creating all these tablespaces on an only instance, because I think that it would be possible to have a reduction of the performances, considering that the tablespaces INDX, TEMP and SYSTEM are the same.
Depends. I would keep each schema in it's own instance if:
1. my schema didn't depend on data in other schemas.
2. my future growth would overwhelm my current hardware platform.
3. I have adequate computing resources; memory, I/O throughput, network bandwidth.

I would combine the schemas into one instance if:
1. I needed data from another schema periodically.
2. I don't forsee much growth on my existing platform.

When putting multiple schemas on one database you end up sharing some resources. This ultimately ends up with one user consuming more than his fair share. You can limit some of the resource contention by spreading out your data on seperate physical devices, but there will always be contention for some resources.

That being said, the customer is always right, right?